While many users, including consumers as well as commercial users, subscribe to telephony services that are delivered using plain old telephony service (“POTS”) networks, users are increasingly subscribing to telephony services that are delivered by means other than POTS. For example, as more and more users subscribe to Internet services, these same users are beginning to receive more than just Internet data services from the Internet providers. Also, community antenna television (“CATV”) subscribers are being offered the providing of services other than broadcast video, using the CATV network infrastructure.
Users have come to expect high reliability from POTS service. Even during severe weather events, POTS service is still typically available, with damage to aerial wires carrying signals in the network being the prime cause of interrupted service. As long as the network conductors, wires and cables are intact, a power loss to a user's location typically does not interrupt POTS service, because the electrical power to operate the system, including the provider's central office as well as the user's telephony equipment, is supplied from the central office. Even if the central office looses offsite power supplied from a utility company, the central office power supply is typically backed up by batteries and temporary electric generators, such as a diesel generator, for example. Thus, even during a power outage at a user's location, users can typically place and receive important telephone calls to determined whether loved ones are safe or to determine whether the utility power service will be restored soon. More importantly, however, a user can place a call to emergency personnel in case someone at the user's location has been injured, typically by entering the universally familiar 911 number sequence.
While the other means of providing telephony services mentioned above are typically reliable, equipment of these POTS-alternatives at a user's location often requires a local power source, such as standard household AC current. For example, if telephony service is provided via an Internet connection, a user would typically need a computer that operates using household power and would need a power backup in case of offsite power loss. Although users may have gasoline or diesel generators, the power backup systems for computers, especially in consumer installations, are typically battery backed-up.
In addition to computers, telephony can also be provided over the internet, but not necessarily through a computer. This is known as voice-over-IP (“VoIP”) and may be provided over a CATV network using devices, such as for example, a VOICE PORT® product as marketed by ARRIS International, Inc. Such network interface devices that interface a user's equipment with a network typically receive a digital data stream using Internet protocol (“IP”) and convert the digital data into an analog signal before being used by a user. Power to these products is typically provided from household current sources, which makes the VOICE PORT® and similar products, such as cable modems, for example, susceptible to loss-of-offsite-power (“LOOP”) events, such as may occur during an ice storm or tornado, for example.
To provide power backup for a LOOP event, batteries are typically used. Rechargeable batteries provide an adequate backup for short duration LOOP events, such as may occur during scheduled maintenance by a utility company, inadvertent damage to power lines by a maintenance worker, or a transformer explosion, for example, which can typically be serviced within a few hours. However, for more extended power outages, which may result from widespread power system damage caused by extreme weather conditions, for example, the depletion life of a fully recharged battery may not be as long as the power outage duration if the telephony equipment remains fully powered during the extent of the power outage.
Thus, there is a need for a method and system for providing battery backup of a device used in a non-POTS telephony system at a subscriber's premises that extends the functional backup period that a battery system can reliably supply power to said telephony device.